In some engines, one end of a cam shaft is extended outside of a cylinder head of the engine, and a cam formed at the extension (of the cam shaft) drives various auxiliary machines. For example, Japanese Unexamined Patent Application Publication No. 2003-184688 and Japanese Unexamined Patent Application Publication No. 2004-270557 disclose a fuel pump as the auxiliary machine driven by the cam. Naturally, the auxiliary machine has a driven member driven by the cam, and the driven member might commonly be a plunger in the case where the auxiliary machine is the fuel pump.
In the case where the cam formed at the extension of the cam shaft drives the auxiliary machine, a housing for storing the auxiliary machine would be attached to the attaching surface formed at one end of the cylinder head. Therefore, the housing holds the driven member driven by the cam, and is attached to the attaching surface so as to cover the cam.
As described above, a cam storage space for storing the cam is formed in the housing attached to the attaching surface formed on the cylinder head. Lubricant (i.e. lubricating oil) needs to be supplied to the cam storage space from a lubricant passage formed in the cylinder head. Additionally, a metal gasket is positioned between the attaching surface of the cylinder head and the housing of the auxiliary machine.
It is required to supply the lubricant to the cam storage space stably, although a small amount of supplied lubricant may be enough. Therefore, it is supposed that a hole communicating between the lubricant passage formed in the cylinder head and the cam storage space could be made, for example, by drilling a small hole with a small drill bit, to produce a hole with a small cross section. However it might require some effort to make the hole for communicating between the cam storage space and the lubricant passage formed in the cylinder head. Further, the drill bit might be easily broken because the diameter of the drill bit would be small.
This invention is made so as to address the above problem. Therefore, the purpose of the invention is to provide a lubricant supply device for an auxiliary machine of an engine, wherein a hole for communicating between the cam storage space in the housing and the lubricant passage in the cylinder head can be made easily by effectively using a metal gasket for attaching the housing to the cylinder head.